1. Field of the Invention
The present invention relates to an apparatus and method for feeding components to an apparatus which automatically places the components on a substrate, such as a printed circuit board or the like.
2. Description of Related Art
Automated equipment exists for picking up a component to be placed on a substrate, such as a printed circuit board or the like and rapidly placing the component into its selected place on the printed circuit board for mounting thereon. Such equipment frequently uses a head for picking up the component and carrying it to the appropriate place on the printed circuit board. The head is usually movable in X, Y, Z, coordinate axes. The placement head shuttles between a pick-up location where one or more components are delivered and the appropriate place on the circuit board for mounting the component.
Such machines are referred to as pick and place machines, and include machines which are manufactured and marketed by Universal Instruments Corporation of Binghamton, N.Y., under the designation xe2x80x9cGeneral Surface Mount Application Machinesxe2x80x9d or xe2x80x9cGSMxe2x80x9d. U.S. Pat. No. 5,649,356 relates to automated pick and place machines.
The known pick and place machines typically distinguish between components of a conventional shape, such as a substantially rectilinear integrated circuit chip, and such components known as xe2x80x9codd formxe2x80x9d components which could include a number of different components of an irregular shape. Such odd form components include USB plugs, MINI DIN sockets, phone jacks transformers, crystals, switches, relays, speakers, transformers, capacitors, and many other different types of components. The present invention can be used with both odd form components, as well as with conventionally shaped rectilinear components.
Some known pick and place machines utilize a tube feeder which feeds the components to the pick-up location within the pick and place machine. One such tube feeder is the xe2x80x9cMulti-Tube Feeder for the Universal GSMxe2x80x9d manufactured and distributed by Universal Instruments Corporation of Binghamton, N.Y. Pending U.S. patent application Ser. No. 09/337,894, the subject matter of which is hereby incorporated herein in its entirety by reference, discloses a tube feeder, and is assigned to the assignee of the present application. U.S. Pat. No. 4,862,578 also discloses a tube feeder.
The pick and place head may include a vacuum head connected to a vacuum source for grabbing the components through a rigid vacuum nozzle presented to the component. For many conventionally shaped components, the vacuum nozzle of the vacuum head can easily find a flat, planar surface on the conventional component for making sufficient contact. However, some components, including some of the odd form components, do not include a predictable geometric shape that consistently presents a flat surface for the vacuum nozzle of the vacuum head to sealingly contact the component. In some situations, the configuration of the odd form component causes the component to wobble or tip slightly as it proceeds along the tube feeder to the pick-up location where it is received by the pick and place machine""s vacuum head. In addition, leads or burrs extending from the component may cause the component to wobble, rotate, or otherwise not present itself in a proper orientation for pick-up by the head.
As a result, when the component is delivered to the pick-up location on the tube feeder, the surface to which the head is intended to make contact may be presented at an angle with respect to the head. For example, the surface of the component to which the head is intended to make contact may be presented at an angle with respect to the plane in which the vacuum nozzle resides. In such a case, the vacuum head may not be able to make a firm, sealed connection or vacuum with the component. As a result, the component may not be picked up by the vacuum head. When this occurs, delays and/or errors may occur.
In addition to vacuum heads, some pick and place machines utilize gripping fingers to grip a component. See fingers 46, 48 in U.S. Pat. No. 4,955,653, the contents of which are incorporated by reference herein in its entirety. Orientation of the component may also be important for gripping or other types of heads in order to ensure dependable results.
It is an object of the present invention to provide a tube feeder for pick and place machines which enables components to be delivered to a receiving location on the tube feeder in such a manner that the component can be easily picked up by a vacuum head with great predictability.
According to one aspect of the present invention, a tube feeder for feeding a plurality of components to a pick and place machine includes an elongated channel having a first end and a second end. The first end of the channel is arranged so as to receive a component from a source of the components and the second end of the channel has a pick-up location. The pick-up location includes an elevated zone on which the components can pivot.
Another aspect of the present invention includes a method of picking up components for delivery to a circuit board in a pick and place machine comprising the steps of moving a plurality of components along a channel from a receiving location to a pick-up location; moving the components to an elevated zone at the pick-up location; pivoting the components on the elevated zone; and picking up the components with a pick-up head. Interaction between the pick-up head and the components causes the components to be oriented in a preferred orientation for pick-up by the pickup head.